Effect on SACC: This would move three species of Sakesphorus into Thamnophilus

Background & New information: As currently recognized by the SACC,
the genus Thamnophilus is composed of 27 species (T.
bridgesi of Central America not covered by SACC, but recognized by AOU
Checklist, 1998). The genus Sakesphorus, of which six species are
currently recognized,has long been thought to be polyphyletic
based on vocal and behavioral similarities of some of its species to Thamnophilus
(Zimmer and Isler 2003).A recent molecular study (Brumfield and
Edwards 2007) sampled individuals from 24 of the 27 described Thamnophilus species,
plus Sakesphorus bernardi, S. canadensis, S. melanonotus, S. melanothorax,
S. luctuosus, and S. cristatus. The data matrix analyzed contained almost
4,000 base pairs of mitochondrial and nuclear sequence data, although sequences
of T. multistriatus, S. melanonotus, S. melanothorax, and
S. cristatus were considerably shorter.

In
phylogenies reconstructed from the ND3 gene, the ND2 gene, and a combined data
matrix of three mitochondrial genes (ND3, ND2, cytb) and two nuclear genes,
Brumfield and Edwards (2007) found that S. bernardi, S. melanonotus, and
S. melanothorax were embedded within Thamnophilus. Bootstrap
support for the inclusion of the three species within Thamnophilus was
high (maximum likelihood bootstrap 100% based on analysis of combined data, 99%
based solely on ND2). A value of 70% of higher is considered to be well
supported, thus, at least from the perspective of mitochondrial data, these
three species clearly fall within Thamnophilus.

In
Brumfield and Edward's (2007) phylogeny, S. bernardi occurred as the
sister taxon to a clade of T. bridgesi and T. atrinucha, the
three forming a clade of species with distributions restricted to the lowlands
west of the Andes. Vocalizations of S. bernardi also support its
placement in Thamnophilus.

The
likely phylogenetic relationships of S. melanonotus and S.
melanothorax have long been problematic.

The
proposal here is to change the genus of S. bernardi, S. melanothorax,
and S. melanonotus to Thamnophilus.

References:

AOU Checklist. 1998.

Brumfield, R. T., and S.
V. Edwards. 2007. Evolution into and out of the Andes: a Bayesian analysis of
historical diversification in Thamnophilus antshrikes. Evolution
61:346-367.

Comments from Remsen: "YES. Having been close to this analysis
for a while, I see no reason not to make this change. Solid genetic sampling,
solid analyses, and sensible results produce a phylogeny that should be
reflected in our classification."

Comments from Stiles: "YES. The data look good, and are
consistent with other evidence. A well-substantiated change."

Comments from Zimmer: "YES. The basis for these transfers is
well substantiated. This also provides yet another example of the importance of
vocalizations versus plumage as taxonomic characters in suboscines. On the
basis of plumage pattern, bernardi is remarkably similar to S.
canadensis and S. cristatus, but vocal characters align it with
Thamnophilus, which is also clearly indicated by the molecular
analysis."